Traffic control markings at street intersections undergo strenuous wear. Many of the markings, such as stop bars or cross-walk markings, extend across the path of travel and are traversed by every vehicle traveling along the controlled lane of travel. Also, at an intersection, vehicles are often in a stop, start, or turning mode, and these modes increase the wear action on the markings. In many geographic areas, sand and chemical treatments are frequently applied at intersections to reduce slippery conditions, and those treatments further aggravate wear conditions.
The most common present markings are lines of traffic marking paints, thicker lines of thermoplastic polymer applied by hot-melt techniques, and preformed tapes or sheet materials adhered to the roadway. As to preformed tapes, see for example, U.S. Pat. No. 4,117,192, which teaches a pavement-marking sheet material comprising a deformable reduced-elasticity polymeric base sheet and a thin support film adhered to the top of the base sheet and having retroreflective elements partially embedded in it. Also, see U.S. Pat. No. 4,248,932, which teaches sheet material that comprises a conformable base sheet such as a dead-soft aluminum foil or a reduced-elasticity polymeric base sheet, and a flexible top layer adhered to the base sheet such as an epoxy-based polymeric system or a polyurethane polymeric system (Example 2); glass microspheres or other particulate material is partially embedded in the top layer, which has a thickness designed to accommodate the particulate material (column 4, lines 12-17).
Although both the thicker thermoplastic lines and the preformed tapes offer significantly better resistance to wear than painted lines, additional resistance and longer-lived markings continue to be desired.